1. Technical Field
The present invention relates to a control rod drive mechanism of a nuclear reactor, and more particularly to a method for recognizing the step movement sequence of a control rod drive mechanism of a nuclear reactor which is capable of accurately recognizing the step movement sequence of the control rod drive mechanism, which draws and inserts a control rod of a nuclear reactor, by estimating and calculating a distance between a stator and a rotor.
2. Related Art
A control rod drive mechanism of a nuclear reactor serves to adjust an electric output of a nuclear power plant by drawing and inserting a control rod with the use of an electromagnetic force so as to control the nuclear reaction of the nuclear reactor. The control rod is drawn out and inserted in by a step unit (commonly ⅝ inch), and a series of sequence movements, generally up to 6 or 7 movements, should be accomplished for one step movement. If there is a mechanical or electric problem in any of the sequence movements, the control rod is apt to be stopped or slowed down. This is a very important problem because it relates to the safe operation of the nuclear power plant and to the efficient management of nuclear fuel. Thus, the sequence movements are the most essential factor in the design and implementation of the control rod controlling equipment. Recently, a method for signal-processing a waveform of an electric current flowing through a coil is used in order to determine the movements, but this method is disadvantageously sensitive to noise since it uses a differential operation.